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Circles

Question
CBSEENMA10009752

A chord of a circle of radius 10 cm subtends a right angleat its centre. The length of the chord (in cm) is

  • 52

  • 102

  • 52

  • 103

Solution

B.

102

Given:  AOB is given as 90°AOB is an isosceles trianglesince OA=OBTherefore OAB= OBA= 45°Thus AOP=45° and BOP= 45°Hence AOP and BOP also are isosceles trianglesThus let AP=PB=OP=xUsing pythagoras theoremx2 + x2 = 102Thus 2x2 = 100x=52Hence length of chord AB = 2x = 102

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